In a radio access system, in order to transmit uplink data to a base station by a user terminal, a bandwidth needs to be allocated to the user terminal. The user terminal transmits bandwidth request information to the base station via a bandwidth request channel in order to allocate the bandwidth and the base station receives the bandwidth request information and then allocates a bandwidth for uplink data transmission to the user terminal. The base station needs to be connected to a large number of user terminals to perform the above-mentioned bandwidth allocating operation or various communication operations. Therefore, lots of studies for efficient data processing and communication operation between the base station and the user terminal are being conducted.